The humidity level in a bath is usually pretty high. The thinner the wood you use the more likely you would have some cup warpage. It might be better if you glued the 5/16" wood to some other solid wood.I am towards the end of a bathroom remodel project and am planning on installing a walnut plant ceiling. I have some old rough-cut walnut about an inch thick that I am thinking of resawing down to 5/16th and putting an 1/8 in chamfer edge on the sides and not doing tongue and groove. Do I need to worry about board movement with moisture in the bathroom? I did install a large CFM exhaust fan knowing I was planning a wood ceiling to help cut down on the moisture in the bathroom.
Also, was looking for thoughts on the best way to finish the walnut boards. I have been looking into Rubio Monocoat but also want something that will be fairly low maintenance that I won't have to redo every couple of years. Should I just use linseed oil then use poly?
Thank you ahead of time for any input you might have.
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I would recommend what ever finish you use you finish both sides to keep it as stable as possible. I don't have any experience with the Rubio finish but I've heard bad things. If it were me I would use a marine grade spar varnish. Epifanes is the best but a little expensive.